Hitherto, a rolling guide device of this type includes a track member and a moving member. The track member has a rolling surface for rolling elements, which extends along a longitudinal direction of the track member. The moving member is assembled to the track member through intermediation of a plurality of rolling elements which roll on the rolling surface, and is reciprocable along the track member. The moving member has a load rolling surface on which the rolling elements roll while bearing a load. The load rolling surface is opposed to the rolling surface of the track member to define a load path for the rolling elements. Further, the moving member has no-load paths for allowing the rolling elements to circulate from one end to another end of the load path. The load path and the no-load paths are continuous with one another to define an endless circulation path for the rolling elements. With such a configuration, the moving member is movable along the track member without being limited in stroke thereof.
A product lifetime of the rolling guide device mainly depends on fatigue in the rolling surface of the track member or the load rolling surface of the moving member. However, when the rolling surface and the load rolling surface as well as the rolling elements such as balls or rollers which roll thereon are not appropriately lubricated with lubricant or bear excessive loads, flaking of the rolling surface or the load rolling surface may occur early, with the result that the product lifetime of the rolling guide device is shortened. Further, the rolling guide device is applicable to various uses, and the progress of fatigue in the rolling surface or the like is inevitably affected by, for example, a use environment and an applied load depending on the use (hereinafter referred to as “use condition”), such as an environment in which special foreign matters fall onto the track member or a use under an environment of an extremely high or low temperature. Thus, in order to allow the rolling guide device to exert its original performance and fulfill its product lifetime, it is desired that an operation condition of the rolling guide device be continuously detected by various sensors, to thereby allow recognition of the state of the rolling guide device, which is varied from hour to hour, based on the detected contents.
For example, for a rotary bearing, as described in Patent Literature 1, the following diagnosis system is proposed. Specifically, a sensor is used to detect sound, vibration, or acoustic emission generated at the time of a rotational operation of the rotary bearing, and an output signal from the sensor is analyzed. Then, a result of the analysis is compared with predetermined reference data to determine whether the rotary bearing has an abnormality.